Subjects: Biology >> Botany submitted time 2023-08-26 Cooperative journals: 《干旱区研究》
Abstract： This study focused on the natural Juniperus rigida population in the loess hilly region of InnerMongolia. The structure and dynamic changes of the population were analyzed using a static life table, survivalfunction, dynamic quantitative analysis, and time series model. The results showed that the population mainlycomprised many individual seedlings, followed by medium and less mature trees. Combined with the dynamicchange index Vpi > 0, the population was a growth type. The survival curve was verified using the curve modeland tended to Deevey-II, indicating that the mortality rate of each age class was stable. Considering the externalinterference, the dynamic index tended to 0, and the population growth is not obvious under the interferencecondition. In the survival function analysis, the population showed a strong survival trend in the early stage,followed by a gradual decline in the middle stage. During the 2-to-8-year period, the number of seedlingsdecreased while middle- aged and adult trees increased. The seedling stage is crucial to the regeneration anddevelopment of the population. Therefore, implementing scientific protection measures for seedlings to promotepopulation regeneration is recommended. Research on the internal mechanisms of the Juniperus rigidapopulation can enrich vegetation construction in arid areas, provide a reference for population management, andprovide a theoretical basis for vegetation protection and restoration in the loess hilly area.
Subjects: Biology >> Botany submitted time 2023-08-26 Cooperative journals: 《干旱区研究》
Abstract： This study focused on the natural Juniperus rigida population in the loess hilly region of InnerMongolia. The structure and dynamic changes of the population were analyzed using a static life table, survivalfunction, dynamic quantitative analysis, and time series model. The results showed that the population mainlycomprised many individual seedlings, followed by medium and less mature trees. Combined with the dynamicchange index Vpi > 0, the population was a growth type. The survival curve was verified using the curve modeland tended to Deevey-II, indicating that the mortality rate of each age class was stable. Considering the externalinterference, the dynamic index tended to 0, and the population growth is not obvious under the interferencecondition. In the survival function analysis, the population showed a strong survival trend in the early stage,followed by a gradual decline in the middle stage. During the 2-to-8-year period, the number of seedlingsdecreased while middle- aged and adult trees increased. The seedling stage is crucial to the regeneration anddevelopment of the population. Therefore, implementing scientific protection measures for seedlings to promotepopulation regeneration is recommended. Research on the internal mechanisms of the Juniperus rigidapopulation can enrich vegetation construction in arid areas, provide a reference for population management, andprovide a theoretical basis for vegetation protection and restoration in the loess hilly area.
Subjects: Geosciences >> Geography submitted time 2023-07-19 Cooperative journals: 《干旱区地理》
Abstract：以库布齐沙漠流动沙地、封沙育草带、防风阻沙林、农田防护林和农田5种下垫面为研究对象，采用野外观测与室内分析的方法对其地表与0~100 cm风沙流中沉积物的粒度及其元素特征进行分析。结果表明：（1）农田和有植被覆盖地表的地表粗糙度较流动沙地明显增加，10 cm处风速减少18%以上，总输沙量平均减少85.6%。（2）不同粒度沙粒中Cu、Fe、Mn、Zn含量差异明显，Cu、Zn元素在粉砂中含量最高，Mn元素在极细砂中含量最高，Fe元素在细砂中含量最多。（3）在风沙流物质再分配作用下，风沙流中粉砂和极细砂含量随着高度的上升而增加，平均较地表增加了约14倍，Cu、Zn、Mn元素含量随之增加，风沙流中随高度上升细砂含量先增加后减少，Fe元素含量也呈现出先增加后减少的趋势，这与原地表中元素含量、地表沉积物不同粒径中元素含量特征密切相关。
Subjects: Agriculture, Forestry,Livestock & Aquatic Products Science >> Soil Science submitted time 2023-05-30 Cooperative journals: 《干旱区研究》
Abstract： Abstract：This study was conducted to explore the influence of desert shrubs and their associated species on soil particle size and nutrient spatial heterogeneity under shrubs. The mixed community of Ammopiptanthus mongolicus and Sarcozygium xanthoxylon and a single plant of A. mongolicus in the Western Ordos National Nature Reserve were selected as the research samples. The surrounding bare sandy land without vegetation cover was used as control. The soil particle size characteristics, nutrient accumulation changes, and the relationship between nutrients and particle size composition under different shrub distribution types were analyzed. The results were as follows: (1) Compared with the mixed community of A. mongolicus-S. xanthoxylon, the volume percentages of soil clay, silt, and fine sand of the single A. mongolicus increased by 0.8%, 0.8%, and 0.71%, respectively. As the types of shrubs decrease, soil particle size became smaller in turn, sorting deteriorated, the fractal dimension became smaller, the soil particle distribution gradually became asymmetric, and the particle composition was concentrated at fine particles. (2) The contents of soil organic matter and alkali- hydrolyzable nitrogen increased by 1.85 g·kg-1 and 8.18 g·kg-1, respectively, with the increase in shrub species. The accumulation of organic matter and available phosphorus by a single A. mongolicus was stronger than that by A. mongolicus-S. xanthoxylon; however, the accumulation of alkali- hydrolyzable nitrogen was slightly poor than that of A. mongolicus-S. xanthoxylon. (3) A. mongolicus-S. xanthoxylon available soil phosphorus content was significantly positively correlated with fine sand content (P<0.05), and A. mongolicus available soil nitrogen and potassium were significantly positively correlated with coarse sand (P<0.05). A. mongolicus-S. xanthoxylon can effectively promote soil granulation and significantly improve soil nutrients. However, the presence of the associated species S. xanthoxylon reduced the enrichment of organic matter and available phosphorus by A. mongolicus.
Subjects: Environmental Sciences, Resource Sciences >> Basic Disciplines of Environmental Science and Technology submitted time 2021-01-25 Cooperative journals: 《干旱区研究》
Abstract：为研究残塬沟壑区苹果园不同果农复合种植模式下土壤入渗能力及其影响因素，采用野外双环入渗法测定了永寿县果-荒（CK）果-草（M1）果-蔬（M2）果-粮（M3）复合种植模式下苹果园的土壤水分入渗参数，使用相关性分析和线性冗余分析研究了土壤入渗特征参数的影响因素。利用3种常用的土壤入渗模型对4种果园入渗过程进行拟合。结果表明：4种果农复合种植模式下果园土壤初始入渗速率在7.18~13.57 mm·min-1；稳定入渗速率在1.87~2.94 mm·min-1；平均入渗速率在3.36~5.65 mm·min-1；累计入渗量在260.51~423.65 mm，各果农复合种植模式苹果园初始入渗速率和平均入渗速率表现为M1>M3>M2>CK；稳定入渗速率和累计入渗量表现为M1>M2>M3>CK，M1样地各入渗指标显著大于其他管理模式样地，CK样地各入渗特征指标最小。相关性分析发现，土壤入渗特征指标与土壤容重、黏粒含量和粉粒含量呈负相关；与最大持水、最小持水量、毛管持水量、毛管孔隙度、非毛管孔隙度、总孔隙沙粒含量呈正相关。线性冗余分析结果表明，土壤粉粒含量、土壤孔隙度、土壤持水量、土壤容重是影响土壤入渗能力的主要的因素。主成分分析评价的土壤入渗能力排序为M1（2.75）>M2（0.04）>M3（-0.63）>CK（-2.17），苹果园林下种植作物能够有效的增加土壤入渗能力。比较3种模型发现，蒋定生模型对残塬沟壑区4种果农复合种植模式果园土壤入渗过程的拟合精度较高（R2=0.97），适用于描述该地区土壤入渗的实际情况。
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